This invention relates generally to injection molding and more particularly to a nozzle manifold used for multi-gate hot tip molding.
Multi-gate injection molding apparatus is well known in which the melt passage branches in a melt distribution manifold and then each branch extends through a heated nozzle secured to the manifold. As seen in the applicant's U.S. Pat. No. 4,094,447 which issued Jun. 13, 1978, it is also known to provide a heated nozzle in which the melt passage branches outwardly to several edge gates. While this is suitable for edge gating, each of the front portions of the nozzle has a flat face which is not suitable for hot tip gating.
The applicant's U.S. Pat. No. 4,921,708 which issued May 1, 1990 does show a multi-gate application with hot tips provided by four elongated probes mounted around a heated nozzle. Other arrangements of multi-tip nozzles are also well known. However, they all have a generally cylindrical shape with a circular rear surface which limits the surface contact with the adjacent manifold. In a system with a large number of gates, it is usually preferable to reduce overall size by having the gates as close together as possible. On the other hand, it is also desirable to maximize heat transfer from and thus surface contact with the adjacent manifold.